#include <iostream>
#include <string>

using namespace std;

int main()
{
	string greetStrings("std::string");
	cout << greetStrings << endl;
	//
	cout << "输入一行文本" << endl;
	string firstLine;
	getline(cin, firstLine);//123

	cout << "输入一行文本" << endl;
	string secondLine;
	getline(cin, secondLine);//456
	//
	string concatString = firstLine  + secondLine;
	cout << concatString << endl;//123456

	string aCopy = concatString;
	cout << aCopy << endl;

	cout << concatString.length() << endl;//6

	return 0;
}